If I cloned my hard drive, and used the cloned hard drive into another computer, would I run into any issues?

[LeSwagMaster]

If I cloned my hard drive, and used the cloned hard drive into another computer, would I run into any issues? For example, would I have to reactivate Windows on both computers or anything stupid like that?

(I'm building a new computer but I don't want to buy a new OS for the new computer)

 

[basroil]

Yes, you would lose activation on both computers and likely have the key rejected from further online activation (phone activation might work)

If you have enough cash to make a new computer, you have enough to buy a new license!

 

[Karadjgne]

Clone the hdd, but leave the original installed where it is, this'll not be seen by Windows as a new pc, since that key is still registered to that motherboard. Install the cloned in the new pc. The copy of Windows will recognize the key as being invalid, at which time you'll need to activate a new key.
The biggest issues other than windows legal issues is the motherboard drivers. They'll be different. So unless you plan on spending time removing them it might be easier to just go ahead and start out with a clean install of windows with its new key and new mobo drivers.